package PTA.javaB;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;
public class ex08 {
    public static void main(String[] args) {
     Scanner sc= new Scanner(System.in);
     int n=sc.nextInt();
     int sum=0;
     double avgradius=0;
     double sumarea = 0;
     int [] arr = new int[n];
     for(int i=0;i<n;i++){
         arr[i] = sc.nextInt();
         sum+=arr[i];//半径总和
     }
     Arrays.sort(arr);//排序
        System.out.println(Arrays.toString(arr));//输出
        for(int i=arr.length-1;i>0;i--){
            System.out.printf(arr[i]+" ");//逆序输出
        }
        System.out.println();//回车
        avgradius = sum*1.0/n;
        System.out.println("radius="+avgradius);//平均半径
        for(int i=0;i<n;i++){
          double area = Math.PI*arr[i]*arr[i];
          sumarea +=area;
        }
        System.out.println("area="+sumarea);

    }
}
